Compaction wheels for earth tampers

ABSTRACT

Compaction wheels for earth tampers. In one embodiment the compaction wheels are of spaced, open ring, spoked construction with sheepsfoot elements projecting outwardly from each ring. The rings have an axial width merging with the width of the spokes and the wheel is constructed and arranged to afford substantially unobstructed full penetration for compaction, with means being provided to cushion the wheel axle from shock loads. In another embodiment the compaction wheels are provided with axle cushioning means which include a plurality of circumferentially arranged, axially disposed shock absorber units each having facing socket members defining a cavity for seating a pair of elastomer cushioning cylinders. The cylinders are formed with axially extending central openings to accommodate expansion of the elastomer material under shock loading.

O UIlltEd States Patent 1 1111 3,724,342 Caron et al. [4 1 Apr. 3, 1973 54 COMPACTION WHEELS FOR EARTH 3,279,339 /1966 Barnum ..94/5o PR TAMPERS 3,313,222 4/1967 Barnum ..94/so PR 896,362 8/1908 Childs ..94/ PR Inventors: Fred Joseph Caron, Citrus Heights; 436.374 9/1890 McLachlen James Oliver Caron, Sacramento; 857,629 6/1907 Jones ..l52/49 George Carrol Gray, Fair Oaks, all of Calif. Primary Examiner-Nile C. Byers, Jr. Assigneez Caron Cumpacmr west Sunk AttorneyFlehr, l-lohbach, Test, Albritton & Herbert mentO, Calif. [22] Flled: 1971 Compaction wheels for earth tampers. In one embodi- [21] Appl. No; 122,746 ment the compaction wheels are of spaced, open ring,

spoked construction with sheepsfoot elements project- Re l ed US Appli ion Dali ing outwardly from each ring. The rings have an axial width merging with the width of the spokes and the [63] fgg m Pan of wheel is constructed and arranged to afford substantially unobstructed full penetration for compaction, with means being provided to cushion the wheel axle (gill ..94/50 from Shock 10a d8 In another embodiment the paction wheels are provided with axle cushioning [58] Field of Search 94/50 50 V means which include a plurality of circumferentially arranged, axially disposed shock absorber units each [56] References Cited having facing socket members defining a cavity for UNITED STATES PATENTS seating a pair of elastorner cushioning cylinders, The cylmders are formed with anally extending central 2,541,007 2/1951 Small ...94/50 PR openings to accommodate expansion of the elastomer g material under shock loading. au sen 3,269,284 8/1966 Caron 94/50 PR 4 Claims, 5 Drawing Figures 114 II III I II II llll 1 1/1 1 1 I22 i i i 11 ea m 5 124 111 I1 1 '1', i 111o ;,\\\x z\\\\\ 141 [4] [29 sea PATENTEDAPR 3 I973 3 724, 342

SHEET 1 OF 5 INVENTORS FRED JOSEPH CARON FIG I JAMES OLIVER CARON GEORGE CARROL GRAY 1%, W 04; M W

ATTORNEYS PATENTEU APR 3 I975 SHEET 2 OF 3 I N v %%RM. OAM TC L N 0 E R V R N A IS C O0 J D mm 4, FJG. V] B ATTORNEYS PATENTEDAPRB I975 3.724.342

sum 3 [1F 3 INVENTORS FRED JOSEPH CARON JAMES OLIVER CARON BY GEORGE CARROL. GRAY 11M, M W

ATTORNEYS COMPACTION WHEELS FOR EARTH TANIPERS CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION This invention relates to improvements in earth tampers and in particular relates to improvements in compaction wheels for earth tampers.

Sheepsfoot rollers, in general, are designed and adapted to be propelled by track laying tractors. This combination is characterized in operation by moderate to low compaction speeds and avoidance of short radius turns where the sheepsfoot could plow out compacted material already in place.

The advent of the rubber-tired tractor characterized by relatively high working speeds and short radius turning created the need for a compatible sheepsfoot tamper which would work at a higher speed and which could be turned in a short radius without destructive effect to the compacted material in place.

The predominant design of the prior art earthtampers or sheepsfoot rollers comprised a large hollow steel drum serving both as a ballast compartment for wet sand or water, and as a support for the outwardly projecting sheepsfoot shanks and caps. The drum in certain arrangements had its own subframe mounted, in turn, to a main or principal frame. Cleaner mechanisms were placed close to the drum surface between the sheepsfoot elements to remove clay and other materials which tended to bridge over. This raker-bar construction frequently imposed a braking effect due to the rakers being operated in close dragcontact with the solid drum.

Construction equipment of the type described incorporate relatively rigid wheels which present serious problems in the failure of the wheel axles and other vehicle components due to the severe shock loads transferred between the wheel and axle as the vehicle operates over the earth or refuse fill. Certain types of construction equipment provide rubber pneumatic tires within the wheel rim for shock isolation. Pneumatic tires of this type have certain drawbacks when used on earth compaction or sanitary land-fillequipment due to the natural hazards incurred which wear the tires and create tire puncture, and with consequent expensive down time for repair or replacement. Furthermore, pneumatic tires of this type when underinflated do not create the necessary friction coefficient with a resulting tendency to slip in the wheel rim, and when over-inflated to stop this slippage they do not irnpart the proper shock absorption characteristics.

Another example of an existing compaction wheel is the shock absorber apparatus of the Barnum U.S. Pat. No. 3,279,339. In this apparatus a plurality of rubber blocks rectangular in cross section are circumferentially mounted between the hub and wheel rim in open-ended sockets with the provision of a central bolt and end plates dismountably holding the blocks in the sockets. The rubber displaces at the outer edges under shock loading, and the presence of the rigid bolt limits the extent of shock absorption.

SUMMARY OF TI-HE. INVENTION AND OBJECTS This invention, in summary, provides in one preferred embodiment a compaction wheel for an earth tamper of the sheepsfoot type. The compaction wheel is adapted for mounting on earth tamper vehicles of differing designs such as an earth tamper having perimeter wheel-frames of a wheel frame assembly which in turn oscillates about a guide member on a main frame structure. The wheels are of spaced, open ring, spoked construction with sheepsfoot elements projecting outwardly from the rings. This construction affords substantially unobstructed full penetration by the wheel structure for compaction. Non-engaging cleaner bars a plurality of circumferentially arranged, axially disposed shock absorber units mounted between a wheel rim, which in turn carries the tamper elements, and an annular plate adapted for mounting to the axle hub. Each shock absorber unit includes a pair of the cushioning cylinders seated between facing, spaced apart sockets, with an axially extending opening through each cylinder to accommodate expansion of the elastomer material under shock loading. This design affords a relatively permanent installation in a manner to effectively isolate the axle and other vehicle components from shock loading on the wheel, and at the same time obviating the problems encountered with existing pneumatic tire shock isolation devices, or with existing solid rubber block shock absorber devices.

Accordingly, an object of the invention is to provide improved compaction wheels for earth tampers.

Another object is to provide a compaction wheel for an earth tamper of the sheepsfoot type in which the wheels are of open ring construction mounted on cylindrical spokes radiating from a hub in a manner to provide substantially unobstructed full penetration for compaction, and with axle cushioning means provided to absorb shock loading.

Another object is to provide a compaction wheel adapted for mounting on construction equipment of varied designs with improved means for absorbing the shock loading between the wheel and vehicle axle.

Another object is to provide axle cushioning means for a compaction wheel with a plurality of circumferentially arranged, axially disposed shock absorber units each comprising facing, spaced apart sockets seating a pair of cushioning cylinders of an elastomer material with axially extending openings through the cylinders for accommodating cylinder expansion under shock loading.

Further objects and features of the invention will appear from the drawings taken in conjunction with the specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary axial section view of a compaction wheel of one preferred embodiment of the invention;

FIG. 2 is a side elevation view, partially broken away, of a compaction wheel of another preferred embodiment of the invention;

FIG. 3 is an axial sectional view taken along the line 33 of FIG. 2;

FIG. 4 is an enlarged, fragmentary sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged, fragmentary sectional view taken along the line 55 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A compaction wheel '73 of the first embodiment of the present invention is shown in FIG. 1. This embodiment provides an improved construction for a compaction or tamper wheel of the type adapted for mounting on the wheel axles of construction equipment of varied designs, e.g., on pull type tampers or as a replacement for the existing wheels of self-propelled construction equipment for use in tamping operations' Details of the construction and operation of one form of an earth tamper to which a plurality of compaction wheels 73 would be mounted are explained in U.S. Pat. No. 3,559,545 issued to Fred J. Caron, one of the applicants herein. Such an earth tamper includes a main frame and a single wheel-frame assembly carrying a pair of wheels, although a pair of wheel-frame assemblies of this type could be provided in side-by-side relationship on a larger main frame in the manner described in said patent.

The compaction or tamper wheel 73 is mounted about a wheel axle 94 which in turn is mounted for free wheeling rotation at its opposite ends in the pillow blocks 95, 96 depending from a wheel-frame assembly 72. A hub 97 of cylindrical shell construction is mounted to the axle by axle cushioning means 98 through end positioned annular plates 99, 100.

Cushioning means 98 comprises an outer barrel 101 spaced from inner sleeve 102, through which the axle is inserted. A pair of elastomer sleeves 103, 104 are mounted at the ends of the cavity formed between the barrel and inner sleeve and are retained in place by outer retainer rings 105, 106 and inner retainer rings 107, 108. These retainer rings are radially spaced from the respective confronting outer barrel or inner sleeve to provide gaps or relief openings through which the end edges of the elastomer sleeves yieldably extrude, deform or displace while absorbing shock loading. The inner and outer end edges of the sleeves 103, 104 are beveled so that, after assembly and compression of the elastomer sleeves, the sleeve ends present a substantially flat surface to the respective relief openings. The elements are assembled by initially inserting the sleeves 103, 104 in their uncompressed condition within the cavity with a suitable jig or fixture used to inwardly compress the sleeves into close fitting contact between the inner sleeve and outer barrel. The end retainer rings are then secured in place as by welding, the wheel axle is inserted through sleeve 102, and the wheel is mounted to the pillow blocks.

The plurality of axially spaced apart rings 58 are rigidly secured to hub 97 by an array of radially extending spokes 109. These spokes are preferably of cylindrical cross-section and of a diameter substantially equal to the ring width so as to merge with the rings to avoid bridging and collection of material between adjacent spokes.

Sheepsfoot earth tamping elements 110 including a shank 1 11 and cap 112 are secured upon and project outwardly from the peripheral surface of each of the rings 58 in evenly spaced relation. The tamping elements 110 on adjacent rings may be staggered relative to each other.

Raker bars 66 are fixedly secured to end members 87 of the wheel-frame assembly 72 and extend through the gaps between adjacent rings on the wheels to prevent rocks, clay and other unwanted material from lodging there permanently. Ballast blocks, not shown, when such are needed, may be mounted upon the main frame to achieve the compaction required by the job specification.

In the operation of the embodiment of the compaction wheel 73 a prime mover, such as a crawler type tractor, is attached to the hitch assembly of a tamper such as that described in said US. Pat. No. 3,559,545 and operated to pull the tamper over the earth or refuse fill. The open-ring tamper wheels 73 are free to turn independently while the wheel-frame assembly 72 is free to oscillate permitting the tamper to be turned in a relatively small space without digging up the previous compacted material. The spaced, open ring, spoked construction of the compaction wheels affords substantially unobstructed full penetration for compaction with the raker bars functioning to clean unwanted material from between the rings and spokes. Furthermore, the earth tamper is simple and rugged in design and may be readily disassembled for easier transport of individual components to the job site.

The embodiment of the invention illustrated in FIGS. 2-5 provides a compaction wheel 114 incorporating means for effectively isolating the axle and other vehicle components from the severe shock load forces encountered during a compaction operation, e.g. as the compaction wheel is pulled at relatively high speeds over undulations or ruts in the ground and rocks, stumps or other obstructions along the path of travel. While compaction wheel 114 is illustrated in the preferred embodiment as incorporating sheepsfoot type tamping elements, it is understood that the invention of this embodiment will have application for use with other types of construction vehicles incorporating rigid wheels such as roller wheels having smooth outer rims and tamper wheels such as those provided with wedge-shaped cleats and the like. Compaction wheel 1 14 of the invention also is adapted for interchangeable mounting on existing construction equipment for com paction operations, such as for interchanging with equipment having a conventional pneumatic tire arrangement for absorbing shock loading.

Compaction wheel 114 is illustrated as adapted for mounting to a flange 115, as by suitable bolts 116, on the hub 117 of an axle 118 which in turn is journaled for rotation on the vehicle main frame.

Wheel 114 comprises a wheel rim 119 of cylindrical shell configuration mounted for rotation with annular plate 120 by axle cushioning means comprising a plurality, shown as six, of circumferentially spaced, axially disposed axle cushioning or shock absorber units 121. The illustrated sheepsfoot tamper elements 122 project outwardly from a plurality, shown as three, of rings 124 concentrically positioned about wheel rim 119 and fixedly secured thereto by an array of spokes 125. The spokes 125 are preferably cylindrical in cross section with a diameter substantially equal and merging with the width of the rings 124.

The plurality of shock absorber units 121 are substantially identical and each unit comprises an inwardly facing socket member 126 mounted to the interior surface of wheel rim 119 and an outwardly facing socket member 127 mounted to plate 120 in radially spaced apart opposing registry with a respective socket 126. Each of the socket members are defined by a segment of a cylindrical shell so that the two members together define a cylindrical cavity for containing a pair of cushioning cylinders 128,129 in end-to-end relationship. Socket member 126 is braced to the wheel rim by four gussets 130,131 while socket member 127 is braced to plate 120 by gussets 132,133. Additionally, a bracing ring 134 provided with semi-circular cutaway portions at its outer periphery is secured as by welding to the ends of socket members 127. A plurality of axially extending gussets 136 are welded to ring 134, socket members 127 and plate 120 for additional rigid support.

The cushioning cylinders 128,129 are of a suitable elastomer material having sufficient strength and durability to hold the wheel rim for rotation with the axle hub under a full range of operating conditions while isolating the axle and other vehicle components from shock loading. A rubber material such as neoprene rubber with a 70 durometer value and with a high heat dissipation factor may be advantageously utilized. This durometer value is varied, as desired, to obtain greater or lesser shock absorbing characteristics to match equipment of varying weight and design.

The two cushioning cylinders are formed with centrally disposed, axially aligned openings 137 to freely accommodate expansion of the elastomer material under shock loading. These cushioning cylinders are separated and retained within the socket cavity by means of a pair of spaced apart semi-circular retainer plates 138,139. The cushioning cylinders are initially oversized in length so that they are compressed when in seated engagement between the socket members after assembly. The cylinders are held in the socket cavity by radially spaced, semi-circular end plates 140,141 secured as by welding to the ends of members 126,127. With the cushioning cylinders firmly held in the sockets in this manner a range of lateral and vertical movement is afforded for the elements of the shock absorber units, in addition to the expansion provided by the through openings 137, as shock loading is absorbed.

An example of one application of the invention of this embodiment is as follows. For a compactor wheel of the sheepsfoot tamper type having an outer diameter of 76 inches for the tamper elements and an inner diameter of 43 inches for the wheel rim six shock absorber units 121 are provided at equally spaced circumferential positions for mounting to the annular plate 120. The material of the cushioning cylinders 128,129

is neoprene rubber having a durometer value and with dimensions in the uncompressed state of 3.2 inches O.D., 0.5 inch [.D. for opening 137, and 7.4 inch in length. After compression and assembly within the socket cavity of 3.5 inch ID. the cylinders are compressed to a length of 7 inches.

In the use and operation of the embodiment for FIGS. 2-5 the compaction wheel 114 is mounted to the desired axle hub on a construction vehicle. The shock forces imparted to the tamper elements as the wheel is pulled or pushed over the earth or refuse fill are transmitted into and largely absorbed by the cushioning cylinders 128,129 to protect the axle and other vehicle components from destructive stresses. The energy imparted to the cushioning cylinders in this manner causes the elastomer material to undergo expansion largely into the central openings 137. in addition the cushioning cylinders are mounted in socket members 126, 127 in a manner affording a range of lateral and vertical movement to accommodate shock absorption.

While the embodiments herein are presently considered to be preferred it will be understood that numerous variations and modifications may be made therein by those skilled in the art and it is intended to cover in the appended claims all such variations and modifications as fall within the true spirit and scope of the inventions.

We claim:

1. For use with an earth or refuse tamper which includes a main frame structure, at least one wheel axle, compaction wheel means including a cylindrical, axially extending hub mounted about said axle, a plurality of axially spaced-apart independently mounted rings positioned concentrically about said hub, radially extending spoke means rigidly mounting said rings to said hub, said spoke means having an axial width merging into the width of said rings, a plurality of radially elongate tamper elements circumferentially spaced about said rings and projecting outwardly therefrom whereby said wheel means affords substantially unobstructed full penetration into the earth or refuse by the wheel structure between laterally adjacent rings, and axle cushioning means between the axle and hub to cushion the axle from shock loads comprising a plurality of inwardly facing, circumferentially spaced sockets of semi-cylindrical shell configuration mounted for rotation with said spoke means, a plurality of outwardly facing, circumferentially spaced sockets of semi-cylindrical shell configuration mounted for rotation with said hub and in radially spaced registry with respective inwardly facing sockets to define plural cylindrical cavities extending axially of the said wheel axle, and a plurality of cushioning cylinders formed of an elastomer material, at least one cylinder being mounted under compression in each cavity, the cushioning cylinders being formed with an axially extending substantially obstructed central opening to accommodate expansion of the elastomer material under shock loading.

2. The compaction wheel of claim 1 wherein a cylin drical rim is concentrically positioned about said hub with said cylindrical spokes extending from the rim to said rings, the inwardly facing sockets are positioned interior of the rim and mounted for rotation therewith, and an annular plate is mounted to said outwardly facing sockets and extends radially inwardly therefrom in connection with the hub of the axle.

3. A compaction wheel for mounting on the hub of an axle of a construction vehicle comprising the combination of a wheel rim positioned concentric around said hub, means interior of the rim for detachably mounting the wheel to said hub, and a plurality of circumferentially arranged, axially disposed shock absorber units mounted between said last-mentioned means and said wheel rim to absorb shock load forces transferred between said wheel and axle, each of said shock absorber units including a pair of radially spaced apart socket members of semi-cylindrical shell configuration which co-operate to define respective cylindrical cavities extending axially of said wheel axle, together with a plurality of cushioning cylinders formed of an elastomer material, each cylinder being mounted under compression within a respective cavity and seated against the associated socket members, the cushioning cylinders being formed with an axially aligned substantially unobstructed opening to accommodate expansion of the cushioning cylinders under shock loading, with the radial spacing between the socket member pairs adapted to accommodate a range of vertical, horizontal and angular relative movement between said socket members under shock loading.

4. The compactor wheel of claim 3 in which the shock absorber units each comprise an inwardly facing socket member mounted interior of the wheel rim and an outwardly facing socket member mounted for rotation with said detachable mounting means, a pair of said cushioning cylinders are provided in end-'to-end relationship within each of said cavities,wall members at the socket ends to retain said cushioning cylinders therein under said compression, together with retainer means mounted to respective socket members between the associated pair of cylinders to hold the latter against gross displacement within the respective cavity. 

1. For use with an earth or refuse tamper which includes a main frame structure, at least one wheel axle, compaction wheel means including a cylindrical, axially extending hub mounted about said axle, a plurality of axially spaced-apart independently mounted rings positioned concentrically about said hub, radially extending spoke means rigidly mounting said rings to said hub, said spoke means having an axial width merging into the width of said rings, a plurality of radially elongate tamper elements circumferentially spaced about said rings and projecting outwardly therefrom whereby said wheel means affords substantially unobstructed full penetration into the earth or refuse by the wheel structure between laterally adjacent rings, and axle cushioning means between the axle and hub to cushion the axle from shock loads comprising a plurality of inwardly facing, circumferentially spaced sockets of semi-cylindrical shell configuration mounted for rotation with said spoke means, a plurality of outwardly facing, circumferentially spaced sockets of semi-cylindrical shell configuration mounted for rotation with said hub and in radially spaced registry with respective inwardly facing sockets to define plural cylindrical cavities extending axially of the said wheel axle, and a plurality of cushioning cylinders formed of an elastomer material, at least one cylinder being mounted under compression in each cavity, the cushioning cylinders being formed with an axially extending substantially obstructed central opening to accommodate expansion of the elastomer material under shock loading.
 2. The compaction wheel of claim 1 wherein a cylindrical rim is concentrically positioned about said hub with said cylindrical spokes extending from the rim to said rings, the inwardly facing sockets are positioned interior of the rim and mounted for rotation therewith, and an annular plate is mounted to said outwardly facing sockets and extends radially inwardly therefrom in connection with the hub of the axle.
 3. A compaction wheel for mounting on the hub of an axle of a construction vehicle comprising the combination of a wheel rim positioned concentric around said hub, means interior of the rim for detachably mounting the wheel to said hub, and a plurality of circumferentially arranged, axially disposed shock absorber units mounted between said last-mentioned means and said wheel rim to absorb shock load forces transferred between said wheel and axle, each of said shock absorber units including a pair of radially spaced apart socket members of semi-cylindrical shell configuration which co-operate to define respective cylindrical cavities extending axially of said wheel axle, together with a plurality of cushioning cylinders formed of an elastomer material, each cylinder being mounted under compression within a respective cavity and seated against the associated socket members, the cushioning cylinders being formed with an axially aligned substantially unobstructed opening to accommodate expansion of the cushioning cylinders under shock loading, with the radial spacing between the socket member pairs adapted to accommodate a range of vertical, horizontal and angular relative movement between said socket members under shock loading.
 4. The compactor wheel of claim 3 in which the shock absorber units each comprise an inwardly facing socket member mounted interior of the wheel rim and an outwardly facing socket member mounted for rotation with said detachable mounting means, a pair of said cushioning cylinders are provided in end-to-end relationship within each of said cavities, wall members at the socket ends to retain said cushioning cylinders therein under said compression, together with retainer means mounted to respective socket members between the associated pair of cylinders to hold the latter against gross displacement within the respective cavity. 